Manufacture of oil-soluble polyhydric phenols



Patented Sept. 1, 1936 MANUFACTURE OF OIL-SOLUBILE POLYHYDRIC PHENOLS Charles P. Wilson, Jr., Houston, Tex.

No Drawing.

1930, Serial No.

Original application December 17,

Divided and this application May 21, 1934, Serial No. 726.728

Claims. (Cl. 260-154) This invention relates to a method of preventing deterioration of oils fats, and rubber, and is applicable to substances liable to oxidation. The process and product will be described more particularly in relation to inhibiting auto-oxidation of motor fuels resulting from pyrolysis of heavy. oils or coal.

Color deterioration and gum formation are known to be the result of oxidation. Color deterioration does not render motor fuel or motor oil unfit for use, but lowers its market value. Gum formation is the result of oxidation of unsaturated hydrocarbons, and when present in motor fuel in small quantities renders the fuel unfit for use in an internal combustion engine. To obtain gumfree and stable products, the usual practice is to remove a substantial quantity of the unsaturated hydrocarbons through treatment with sulfuric acid, or through the control of the cracking plant in such a manner as not to produce a high con- 'centration of the unstable unsaturated hydrocarbons. Control of the cracking process in this way sometimes results in a lower percentage of cracked fuel, and the sulfuric acid treatment always results in a loss, which in many cases runs as high as 5% of the motor fuel produced. This treatment is costly and wasteful, and also results in a lowering of the anti-knock value of the motor fuel.

The primary object of the invention is the man-- ufacture and use of an oxidation inhibitor which, when added in minute quantities, prevents deterioration of hydrocarbons and various oils liable to oxidation. It is particularly useful in the manufacture and marketing of motor fuel containing unsaturated hydrocarbons liable to oxidation;

, since it not only inhibits gum formation in storage, but actually reduces the gum yield when the cracked product to which the inhibitor has been added is tested for gum by the copper dish method. In the majority of cases only a minute quantity of the inhibitor, the cost of which is almost negligible, is required to reduce the result of the copper dish test to any desired specification. Results of tests made with identical cracked gasolines with and without the addition of the stabilizing compound are shown hereunder:

Corrnx DISH Tss'rs Sample 1 Amount of inhibitor Gum (gm. per 100 m) (gins. per 100 cc.)

Nil 0. 103 0. 002 0. 048 0. 005 0. 00s 0. 018 0. 025

Sample 2 Nil 11 183 0.000: a 101 (10014 0.966 5 0.0035 0.008 0.007 0.011

hydroquinone, ortho-aminophenol, para-aminophenol, paraphenylene diamine, methylaminophenol, and alpha-naphtha].

Numerous other compounds, such as cresol, dimethylaniline, etc., have a slight stabilizing effect, but my experience has been that as a general rule only aromatic compounds with two hydroxyl and/or amino groups in the ortho or para positions of the benzene ring will completely prevent an oxidation, although it will be noted that alphanaphthol, which has only one hydrowl group, is an exception. The presence of other groups in the benzene ring in addition to the above mentioned does not destroy the inhibiting action.

All of the above mentioned substances except alpha-naphthol are more soluble in water than in oil, in which they are nearly insoluble, and they are not satisfactory for use in practice for the commercial stabilization of motor fuels on account 30 of the fact that it is diifiult to prevent the latter from coming into contact with water. Naphthol cannot be used, since it causes motor fuel to deteriorate in color, although it is satisfactory as regards solubility. 35

I have found that if an alkyl or aryl group is substituted for a hydrogen atom in these compounds, their solubility in water is decreased and their solubility in oil is increased without an appreciable loss in their power to inhibit oxida- 40 tion. The greater the number of alkyl or aryl groups which can be substituted in the benzene ring, the more soluble is the resulting compound in the hydrocarbon to be stabilized and the less soluble in water.

The new and novel features of the present invention are: the production of oil-soluble oxidation inhibitors from certain types of oil-insoluble phenolic or amino compounds, by substitution of one or more alkyl or aryl groups for hydrogen atoms; an improved method of introducing an alkyl group into a phenol; and the utilization of turpentine, a liquid sulfur dioxide extract of an oil, or the unsaturated hydrocarbons derived from the pyrolysis of oil or coal, as the base or stock from which the substituted phenolic or amino compound is produced; oils containing mixed unsaturated hydrocarbons are very much cheaper than the pure unsaturated compounds,

but are equally satisfactory for the preparation of the substituted compound.

The introduction of. alkyl groups is effected by a modification of the method of Koenigs. (Ber.

preferably contain a large percentage of unsaturated hydrocarbons, as high concentrations of the latter cause the reaction to take place more readily.

2. The use of dilute sulfuric acid (about 50%) instead of concentrated acid. This prevents loss of the phenolic compound by eliminating side reactions such as the formation of acetates.

3. The use of. a much smaller quantity of sulfuric and acetic acid, thus reducing the cost of manufacture.

4. Carrying out the reaction at an elevated temperature with agitation. This reduces the time required to a few hours.

5. The use of a considerable excess of unsatu-. rated compounds, in order to avoid loss of the more costly phenol.

6. Incomplete removal of acetic acidfrom the solution of alkyl substituted phenol. A trace of acid present in the solution acts as a preservative, preventing oxidation of the compound itself before it is added to the oil to be stabilized.

'1. The use of adilute solution of a mineral acid for extracting the acetic acid instead of water or ammonium carbonate. Oxidation of the compound during the washing is thus prevented.

It will'be noted that by alkylation of the various oil-insoluble oxidation inhibitors, such as pyrogallol and aminophenol, in various ways, an almost infinite number of different compounds can be obtained which would be suitable for inhibiting the oxidation of oils. For the preparation of the various types of compounds, a number of different methods are available. For example, amyl pyrogallol may be prepared by the action of amyl alcohol on pyrogallol in the presence of anhydrous zinc chloride; and aminophenol can be alkylated by heating under pressure I with alcohols; or the reaction between pyrogallol andunsaturated hydrocarbons will take place to some extent without a catalyst, or with aluminum chloride. I have,'however, found that the cheapest and easiest compounds to manufacture are those prepared from pyrogalloi by the method described above. Catechol' also gives good results by this method, but is more expensive. Examples of the preferred method of preparation using cracked distillate and turpentine are given below:

Five parts by weight of powdered pyrogallol, ten parts of glacial acetic acid, one part of 50% sulfuric acid, and ten parts of cracked distillate are placed in an acid-resisting container fitted with a stirrer and a reflux condenser, and supplied with facilities for heating. The mixture is agitated violently, and heated to boiling- The agitation and heating are continued for two hours, '15 parts of cracked distillate being grad ually added during this period. After two hours, when substantially all of the pyrogallol should have enteredinto combination with the unsaturated hydrocarbons present, the agitation is stopped andthe product allowed to cool in an oxygen-free atmosphere. The reaction which occurs is probably as follows:

acmcm plus 0.114011). gives ncntcmctmwm' olefine pyrogallol stabilizer The resulting mixture consists of a solution of the oxidation inhibitor and acetic acid in the oil which supplied the unsaturated hydrocarbons, and a layer of sludge on the bottom of the containing vessel. Twenty parts of 0.1% sulfuric acid are introduced, and the mixture is agitated for fifteen minutes for the purpose of removing excess acetic acid. The washing also causes any substituted compound contained in the sludge to return to the oil solution. The lower layer is drained off, and the extraction repeated twice. The solution of oxidation inhibitor thus prepared is then run into a storage vessel, preferably of copper or wood.

When turpentine is used, forty parts of pyrogallol are dissolved by heating and agitation in sixty parts of glacial acetic acid. One part of 50% sulfuric acid'is added, and a hundred parts fresh turpentine introduced while the mixture is being agitated. Heat is evolved, and care must be taken that the temperature does not rise above 100 C. When all the turpentine has been added, the mixture is maintained at about 90 C. until the reaction is substantially complete. After cooling, it may be diluted by a suitable oil. It is then washed as in the previous example. The amount of the substituted compound formed is substantially twice the weight of pyrogallol used. I have found that acetic acid acts as a preservative of the compound, but most of it must be removed, as it would cause the motor fuel to which the above described inhibitor has been addedto become corrosive. The acetic acid may be removed by extraction with any suitable solvent, such as water or a -mineral acid, or by other suitable methods such as distillation, instead of by dilute sulfuric acid as described in the above examples.

It has been found that the substituted compound when prepared as described above may be stored for a long period of time, at least as long as two years as shown by practical tests, without losing activity as a stabilizer.

I have found that a compound as thus prepared is'acidic and that it can be removed or destroyed by shaking with alkalies, such as sodium carbonate or caustic soda. It is, therefore, necessary to prevent the motor fuel from coming into contact with alkaline substances after the addition of the inhibitor. The compound is also destroyed by organic peroxides, and to prevent this the motor fuel must be perfectly fresh and free from peroxides when the compound is added. a

The gum content of Samples 3 and 4 shown hereunder has been determined by the U. S. Bureau of Mines Steam Oven Method, in which a 20 cc. sample of motor fuel is evaporated in a steam oven from which oxygenis excluded. The gummy residue obtained in this manner is considered to represent the actual or inherent gum present in the fuel.

The gum content of Samples 1 and 2 hereinbefore described under "copper dish tests" was evaporation and although a sample of cracked .inhibitor, are given below.

gasoline gives a considerable residue by this method, the same sample might be found to be entirely free from inherent gum as determined by the steam oven method.

Results of storage tests made on identical cracked gasolines, with and without addition of The samples consist of cracked gasoline stored in dark in glass bottles vented to atmosphere;

Sample No. 3

Steam oven gum (gms. per Color-Baybolt chromom- 20 cc.) eter Time 0! storage (weeks) Without inhibitor Without With 0.001% inhibitor inhibitor plus plus plus aas'aesca aassscws a assssaaeaaase Sample No. 4

Without inhibitor Without With 0.00am With 01113575 inhibitor inhibitor inhibitor E 5: Bi8

plus

From the above description it will be evident that while I have described and claimed the preferred embodiment of the invention, it is to be understood that I reserve the right to make all changes properly falling within the spirit oi the invention and without the ambit of the prior art.

This application is a divisionoi my application Serial No. 503,095, filed December 17, 1930.

I claim:

1. A process for the preparation or oil-soluble phenols, which comprises reacting a terpene hydrocarbon material with a phenol in the presence of acetic acid and a small amount of sulfuric acid.

2. A process for the preparation oi oil-soluble phenols, which comprises combining a commercial terpene hydrocarbon oil with a phenol in the presence of acetic acid and a small amount of sulfuric acid. 3. A process for the preparation of oil-soluble polyhydric phenols, which comprises condensing a polyhydric phenol with a terpene hydrocarbon small amount oi. sulfuric acid.

With 0.001%

inhibitor trihydric phenols, which comprises condensing 10 turpentine with a trihydric phenol in the presence of heat and dilute sulfuric acid.

7. A process according to claim 6 in which the condensing operation is carried out in the presence of a mixture containing a relatively large amount of acetic acid and a relatively small amount of sulfuric acid.

8. A process for the preparation of oil-soluble polyhydric phenol compounds which comprises reacting a polyhydric phenol having hydroxyl 20 groups in the ortho position with turpentine in the presence of acetic acid and a small amount of sulfuric acid.

9. A process according to claim 8 in which the polyhydric phenol is pyrogallol.

10. A process according to claim 8 in which the polyhydrlc phenol is pyrocatechol.

11. A process for the preparation of oil-soluble polyhydric phenols which comprises reacting a polyhydric phenol having hydroxyl groups in the 30 para position with turpentine while in the presence of acetic acid and a small amount of sulfuric acid.

12. A process according to claim 11 in which the polyhydric phenol is hydroquinone.

13. A process for the preparation of oil-soluble polyhydric phenols which comprises condensing oil of turpentine with Doly ydric phenols in the presence of acetic and a trace of 25-100% suliuric acid.

14. A process for the preparation of oil-soluble polyhydric phenols which comprises condensing oil of turpentine with polyhydric phenols in the presence of acetic acid and a trace of 25-100% sulfuric acid and subsequently washing out the excess acetic acid with a very dilute mineral acid. 15. A composition of matter consisting essentially of an oil-soluble condensation product of a phenol and a commercial terpene hydrocarbon oil, said product being a non-resinous oil, and containing components of said terpene hydrocarbon oil as substituent groups.

16. A mixture of oil-soluble phenol derivatives consisting essentially of phenol condensed with oil of turpentine, said derivatives being non-resinous and having components of said oil of turpentine as substituent groups.

17. A mixture of oil-soluble polyhydric phenol derivatives consisting essentially of a polyhydric phenol condensed with a terpene hydrocarbon 011, said derivatives-being non-resinous and having components of said terpene hydrocarbon oil as substituted groups. 18. A mixture of polyhydric phenols consisting essentially of substituted poly ydric phenols containing ingredients oi turpentine as substitucuts.

19. A mixture of trihydric phenols consisting essentially of substituted trihydric phenols containing unsaturated hydrocarbon components of turpentine as 'substituents.

20. Acomposition of matter consisting essentially of a mixture of substituted dihydric phenols containing components of turpentine as substitu- 21. A composition of matter consisting essentially of a mixture of homologues of hydroquinone, said homoiogues containing components of turpentine as substituted groups.

22. A composition of matter consisting essentially of derivatives of pyrogailol, said derivatives being non-resinous and containing components of turpentine as substituted groups.

23. A mixture of pyrocatechoi homologues consisting essentially of pyrocatechol condensed with turpentine, said homologues being non-resinous and. containing components of the turpentine as substituted groups.

24. A composition of matter consisting essentially of a mixture of polyhydric phenol derivatives, said derivatives being non-resinous and containing hydroxyl radicals in the ortho position and components of turpentine as hydrocarbon substituents.

25. A composition of matter consisting essentially of a. mixture of polyhydric phenol derivatives, said derivatives being nonresinou s and having hydroxyl radicals inthe para position and components of turpentine as hydrocarbon substituents.

CHARLES P. WILSON, JR. 

